Process for refining hydrocarbon oils



Feb. 6, 1934. J. A. BUCHE L El AL 1,945,516

PROCESS FOR REFINING HYDROCARBON OILS Filed July 18, 1929 Patented F eb. 6, 1934 PATENT oFFicE UNITED STATES raocess Foa arrange nrnaocmon of Delaware Application July 18, 1929, Serial No. 369,310, and

in the Netherlands July 23, 1928 29 Claims. (01. 196-37) Our invention relates to a process for refining hydrocarbons by extracting with liquid sulphur dioxide. More particularly, the invention relates to a method of improving the extraction by the use of an auxiliary substance in connection with the liquid sulphur dioxide.

} It is known that hydrocarbons,- for instance fractions obtained in the distillation of petroleum, can be refined with liquid sulphur dioxide. This process, called edeleanuization after the name of the inventor, has as its main object the removal of the aromatic compounds. It consists in principle in bringing the material to be refined in contact with liquid S0: at temp ra tures of about degrees C., which causes two layers to form. The upper layer, the rafllnate layer, contains the more or less aromatic-free material, whilst the lower layer, the extract layer, consists of liquid SO: in which the aromatics are mainly dissolved.

In the attached drawing (Fig; 1) a graphic representation is given of the proportions existing according to the phase-rule method. It is assumedthat'the system can be considered to 5 consist of three components, namely non-aromatics, aromatics andpsulphur dioxide, respectively indicated by .NA, A and S0z.'- The curve e g f is the binode; e then represents the solubility of NA in $02 when the NA content is large, I the corresponding solubility of NA in S02 when the NA content is small. The area enclosed by the binode and the part e f of the horizontal axis is the heterogeneous field in which dissociation takes place into two phases differing quantitatively in composition. The part e g is the geometrical place of the phases rich in NA (raflinate layers), the part I 9 that of the phases poor in NA (extract layers) in equilibrium with the first; g is the critical point'at which'the compositions of the two phases become'quantitativelyequal.

. It has now been found that as the aromatic content of the raihnate layer decreases so the ratio of the aromatic content in the extract layer that in the rafiinate layer, becomes smaller, in consequence of which the effect of the treatment by repeated extractions becomes unfavourable. With a high aromatic content this ratio exceeds unity; with a lower aromatic content it becomes less and may decrease to below unity.

in the heterogeneous field it is; immediately seen what the proportion is between the aromatic content of the extract and rafllnate layers. With a positive gradient in respect to the horizontal axis the proportion is greater, with a negative gra- From' the position of the canjugational line s' are I a; whilst when the mixture h is treated with the same percentage of S02, forming phases w and :c,

the ratio is From this it is apparent that the greatest refln- 15 ing effect is obtained with a relatively high aromatic content as compared with that'obtaine'd with a low aromatic content, that is to say: the last remains of aromatics are removed more slowly. 4

The object of this invention is to provide means by'which also with a low aromatic content a satisfactory refining efiect is always obtained, i. erby which the ratio of aromatic content in the extract layer to aromatic .content in the rafllnate s5 layer is as large as possible.

This object can be obtained according to our invention by adding to the material to be treated-logically not before the aromatic content is reduced, for instance after primary extraction with liquid S02 alone-substances which bring about a favourable change in the saidratio.

. As such may be considered, for instance, benzol and toluol, which increases the percentage of components soluble in S0: so as to attain the object described above. v An object of this invention is to effect the ex: traction with liquid sulphur dioxide in the presence of an auxiliary substance which increases the percentage. of components soluble'in liquid sulphur dioxide. a

In order to facilitate control over the conditions then arising recourse is again had to the representation usual in the science of phases according to Fig. 2, in whichlbenzol, indicatedby B, occurs as the Iourth'component in the system. Although the most obvious representation would be a tetrahedron with the four components 'in the comers; preference has been given to a 'partly rectangular form, which may be as being constructed from Fig. 1 by marking 01f the B content perpendicular to the drawing plane. A triangular prism is then obtained, of which the perpendicular through A represents mixtures containing only. A and B. Thus any plane parallel to the base indicates a composition in which A and B occur in constant proportion. One may, therefore, speak of the 0%-B plane (the base shown in Fig. 1), the 50%-B plane (Fig. 2) and so on. With this method of representation the proportions between the other components, with varying composition of the total aromatics (i. e. the aromatics A originally existing plus the benzol B added), come better to the fore than in a tetrahedron.

In Fig. 2 the 50%-B plane is shown by way of example. The heterogeneous field is enclosed by the lines e'f and f'g'e.

If in the 0%-B plane a railinate layer i had been obtained (Fig. 1), then on $02 being added up to say :11 a rafflnate layer w and an extract layer a: would result with an unfavourable refining effect. If, however, a quantity of benzol is added equal to the quantity of aromatics already present (whereby one comes to the 50%-B-plane) then a proportion of A+B concentrations in extract and raffinate layers (Fig. 2) is obtained, which is considerably more favourable With an absolutely equal distribution of A and B in extract and ramnate layers this proportion would be just as favourable as with A alone; it is true that the distribution is not so favourable as this and in the extract layer with high benzol content there is relatively more B, but this difference is not such as to neutralize the favourable efiect of the process described, and certainly not when the drawn-off extract layers contain little benzol. The treatment should, therefore, preferably be so conducted that when beginning with NA+A and B+SO2 one obtains NA+B+ little $02 as rafiinate and SOz+A-1.-1itt1e benzol as extract. This is attained by making use of the counter-current method of extraction.

Example Working on a Venezuelan spindle oil distillate with 28% A, and treating with 200% by weight S02 in counter-current, a raflinate with 4% A is obtained; yield 71%.

This raflinate treated with 200% S02 and 20% benzol (the quantities arecalculated on the raffinate) produces a record ramnate with 2.5% A; yield 67% (calculated on distillate).

When this second raffinate is again treated with the same quantity of SO2+B, without the old S02 and benzol first being evaporated, the third rafiinate has 1% A; yield 63%.

If, however, the first raflinate mentioned above were again edeleanuized with only S02, there would be produced by treating the first raflinate once with 200% S02 a rafilnate with 3% A'and yield 69%, whereas if the first rafiinate had been treated twice with 200% S02 the result would have been a rafiinate with 2.5% A and yield 68%.-

Even on further treatment with $02 only the percentage of 'A in the raflinate is reduced but very little, so that araflinate with 1% A is hardly attainable. a

It is obvious that instead of benzol another suitable substance having the favourable effect described above can be' taken, the application of .ers, either separately or together with the S02,

which then likewise comes within the scope of the present invention.

Further the benzol or other agent used can be recovered from the raflinate and the extract layin a known manner, for instance by distillation followed, if necessary, by fractioned condensation. If recovered together with the $02, a reparation can be carried out to advantage in a known manner.

Having described our invention and illustrated the same, but without anyintent to be limited thereby, what we claim is as follows:

1. A process for the manufacture of refined transformer, spindle and lubricating oils from a mixture of heavy hydrocarbons containing aromatichydrocarbons, comprising extracting said mixture with liquid sulphur dioxide in the presence of a fluid aromatic hydrocarbon having the character and action of benzol to increase the content of components soluble in liquid sulphur dioxide, whereby the percentage of initial materials soluble in liquid sulphur dioxide in said mixture of hydrocarbons is increased and a separation into an'extract layer and a rafilnate layer is obtained.

2. A process for the manufacture of refined transformer, spindle and lubricating oils from a mixture of heavy hydrocarbons containing aromatic hydrocarbons, comprising extracting said mixture with liquid sulphur dioxide in the presence of a fluid aromatic hydrocarbon having the character and action of benzol and separable from the raffinate layer by distillation, to increase the content-of components soluble in liquid sulphur dioxide, whereby the percentage of initial materials soluble in liquid sulphur dioxide in said mixture of hydrocarbons is increased and a separation into an extract layer and a rafiinate layer is obtained. 1

3. A process for the manufacture of refined transformenspindle and lubricating oils from a mixture-of heavy hydrocarbons containing aromatic hydrocarbons, by means of liquid sulphur dioxide, comprising adding to said mixture in ad-. dition to liquid sulphur dioxide a fluid aromatic hydrocarbon having the character and action of benzol and separable from the rafilnate layer by distillation, to increase the content of components soluble in liquid sulphur dioxide, whereby the percentage of materials soluble in liquid sulphur dioxide in said mixture of hydrocarbons is increased, and allowing the mixture to separate into an extract layer and a rafiinate layer.

4. In the process for the manufacture of refined transformer, spindle and lubricating oils from a mixture of heavy hydrocarbon containing aromatic hydrocarbons, by means of liquid sulphur dioxide, the step of adding to the liquid sulphur dioxide a fluid aromatic hydrocarbon having the character and action of benzol to increase the contentof components soluble in liquid sulphur dioxide, by means of which the ratio of high boiling aromatic content in the extract layer to high boiling aromatic content in the raflinate layer is increased.

5. A process for refining petroleum lubricating oil fractions containing undesired aromatics, comprising extracting the fraction with liquid sulphur dioxide in the presence of a fluid aromatic hydrocarbon having the character and action of benzol to increase the content of components sol-' uble in liquidsulphur dioxide and further characterized by being substantially free ,from the non-benzenoid constituents of extracts and by be- 150 presence of said added aromatic hydrocarbon causing an increased extraction of the undes1red aromatics initially in said fraction.

6. A process for refining petroleum lubricating oil fractions containing substantial percentages of undesired aromatics, comprising extracting the fraction with liquid sulphur dioxide alone to produce a raffinate containing a small amount of arcmatics; then further reducing the content 'of initial aromatics by extracting saidrafiinate with liquid sulphur dioxide in the presence of a fluid aromatic hydrocarbon having the character andv action of benzol to increase the content of components soluble in liquid sulphur dioxide and also characterized by being substantially free from the non-benzenoid constituents of extracts and by being separable from the fraction by distillation.

7. A process for the manufacture of refined transformer, spindle and lubricating oils from a mixture of hydrocarbons containing aromatic hydrocarbons, comprising extracting the mixture with liquid sulphur dioxide alone to produce a rafiinate containing a small amount of aromatics; then further reducing the content of initial aromatics by extracting said rafiinate' with liquid sulphur dioxide in the presence of a fluid aromatic hydrocarbon having the character and action of benzol to increase the content of components soluble in liquid sulphur dioxide, whereby Y the percentage of initial materials soluble in liquid sulphur dioxide in said raflinate is increased and a separation into a second extract and rafiinate layer is obtained.

8. A process for the manufacture of refined transformer, spindle and lubricating oils from a mixture of hydrocarbons containing aromatic hydrocarbons, comprising extracting the mixture with liquid sulphur dioxide alone to produce a raflinate containing a small amount of aromatics, then further reducing the content of initial aromatics by extracting said raf'nnate with liquid sulphur dioxide in the presence of a fluid aromatic hydrocarbon having the character and action of benzol and separable from the raffinate layer by distillation, to increase the content of components soluble in liquid sulphur dioxide, whereby the percentage of materials soluble in liquid sulphur dioxide in said rafiinate is increased and a separation into a second extract and raflinate layer is obtained.

9. A process for the manufacture of refined transformer, spindle and lubricating oils from a mixture of hydrocarbons containing aromatic I hydrocarbons, comprising extracting the mixture with liquid sulphur dioxide plus a fluid aromatic.

hydrocarbon having the character and action of benzol to increase the content of components soluble in liquid sulphur dioxide, the presence. of said aromatic hydrocarbon causing an. increased extraction of the aromatics initially in said mixture of hydrocarbons.

10. A process for the manufacture of refined transformer, spindle and lubricating oils from amixture of hydrocarbons containing aromatic hydrocarbons, comprising extracting the mixture by the counter-current method with liquid sulphur dioxide plus a fluid aromatic having the character and action of benzol to increase the cg'mtent of components soluble in liquid sulphur dioxide, whereby the percentage of initial materials soluble in liquid sulphur dioxide in said mixture of hydrocarbons is increased. 7

11. A process for the manufacture of refined transformer, spindle and lubricating oils from a mixture of hydrocarbons containing aromatic hydrocarbons, comprising extracting the mixture with liquid sulphur dioxide alone to produce a railinate containing a small amount of aromatics, then further reducing the content of initial aromatics by extracting saidraflinate with liquid sulphur dioxide plus a fluid aromatic hydrocarbon having the character and action of benzol toincrease the content of components soluble in liquid sulphur dioxide, the presence of said aromatic hydrocarbon causing an increased extraction of the aromatics initially in said mixture of hydrocarbons.

12. A process for the manufacture of refined transformer, spindle'and lubricating oils from a mixture of hydrocarbons containing aromatic hydrocarbons, comprising extracting the mixture with liquid sulphur dioxide alone to producea raflinate containing a small amount of aromatics, then further reducing the content of initial aromatics by extracting said raffinate by the counter-current method with liquid sulphur dioxide plus a fluid aromatic having the character and action of benzol to increase the content of components soluble in liquid sulphur dioxide, the presence of said aromatic hydrocarbon causing an increased extraction of the aromatics initially in said mixture of hydrocarbons.

13. A process for refining petroleum 1ubricating oil fractions containing undesired aromatics, comprising extracting the fraction with liquid sulphur dioxide plus a fluid aromatic hydrocarbon having the character and action of benzol to increase the content of components soluble in liquid sulphur dioxide and further characterized by being'substantially free from the nonbenzenoid constituents of extracts and by being separable from the fraction by. distillation, the presence of said aromatic hydrocarbon causing an increased extraction of the undesired aromatics initially in said fraction.

14. A process for refining petroleum lubricating oil fractions containing substantial percentages of undesired aromatics, comprising extracting the fraction with liquid sulphur dioxide alone to produce a rafiinate containing a small amount of aromatics, then further reducing the content of initial aromatics by extracting said raffinate with liquid sulphur dioxide plus a fluid aromatic hydrocarbon having the character and action of benzol to increase the content of com ponents soluble in liquid sulphur dioxide and further characterized by being substantially free from the non-benzenoid constituents of extracts and by being separable from the ra'ifinate by disvfined transformer, spindle and lubricating oils from a mixture of heavy hydrocarbons containing aromatic hydrocarbons, by means of liquid sulphur dioxide, the step of addingbenzol to the liquid sulphur dioxide, by means of which the ratio of high boiling aromatic content in the extract layer tohigh boiling aromatic content in the rafiinate layer is increased.

1'7.'A process for the manufacture of refined transformer, spindle and lubricating oils from a mixture of heavy hydrocarbons containing aromatic hydrocarbons comprising adding benzol to said mixture whereby the percentage of total aromatic hydrocarbons in the extract and raifinate layers is increased and adding liquid sulphur dioxide to said mixture to separate the hydrocarbons into an extract layer and a rafiinate layer.

18. A process for refining petroleum lubricating oil fractions containing undesired aromatics, comprising extracting the fraction with liquid sulphur dioxide in the presence of benzol substantially free from the non-benzenoid constitutents of extracts, the presence of said benzol causing an increased extraction of the undesired aromatics initially in said fraction.

19. A process for the manufacture of refined transformer, spindle and lubricating oils from a mixture of heavy hydrocarbons containing aromatic hydrocarbons, comprising extracting said mixture with liquid sulphur dioxide plus benzol.

20. A process for refining petroleum lubricating oil fractions containing undesired aromatic hydrocarbons comprising extracting the fraction by the counter-current method with liquid sulphur dioxide plus benzol, the presence of said benzol causing an increased extraction of the undesired aromatics initially in said fraction.

21. 'A process for refining petroleum lubricating oil fractions containing undesired aromatics, comprising extracting the fraction with liquid sulphur dioxide plus benzol substantially free from the non-benzenoid constituents of extracts.

22. A process for the manufacture-of refined transformer, spindle and lubricating oils from a mixture of heavy hydrocarbons containing aromatic hydrocarbons comprising extracting said mixture with liquid sulphur dioxide alone, separating the extract layer from the rafiinate layer and extracting said raifinate layer with liquid sulphur dioxide plus benzol, the presence of said benzol causing an increased percentage of initial materials in the mixture of hydrocarbon oils in said rafiinate layer to be soluble insaid liquid sulphur dioxide.

23. A process for refining petroleum lubricating oil fractions containing substantial percentages of undesired aromatic hydrocarbons, comprising extracting the fraction with liquid sulphur dioxide alone to produce a raflinate containing a small amount of aromatics then further reducing the content of initial aromatics by extracting said raflinate by the counter-current method with liquid sulphur dioxide plus benzol, the presence of said benzol causing an increased extraction of the undesired aromatics initially in said raifinate. 1

24. A process for refining petroleum ,lubricatingoil fractions containing substantial percentwith liquid sulphur dioxide plus benzol substantially free from the non-benz enoid constituents of extracts.

25. A process for refining petroleum lubricating oil fractions containing large amounts of arcmatics which it is desired to remove, comprising extracting the fraction at least once with liquid sulphur dioxide alone in order to produce a raffinate containing a small amount of aromatics, then further extracting said rafiinate with liquid sulphur dioxide plus benzol, this latter extraction being repeated until the amount of initial aromatics contained in the final raffinate is less than would result from repeated extraction of the original fraction with pure liquid sulphur dioxide alone.

26. A process for refining petroleum lubricating oil fractions containing undesired aromatic hydrocarbons, comprising extracting the fraction by the countercurrent method with liquid sulphur dioxide plus about an equal amount of benzol.

27. A process for refining petroleum lubricating oil fractions containing substantial percentages of undesired aromatic hydrocarbons, comprising extracting the fraction with liquid sulphur dioxide to produce a rafiinate containing a small amount of -aromatics,'then further reducing the content ofaromatics by extracting said raifinate by the counter-current method with liquid sulphur dioxide plus about an equal amount of benzol.

28. A process for refining petroleum lubricat ing oil fractions containing aromatics which it is desired to remove, comprising extracting the fraction in the counter-current manner with about 200% by weight of liquid sulphur dioxide alone, then extracting the raflinate in the counter-current manner with about 200% by weight of liquid sulphur dioxide plus about 20% by weight of benzol, and removing from the final rafl'inate any sulphur dioxide and benzol contained therein.

29. A process for refining petroleum lubricating oil fractions containing aromatics which it is desired to remove, comprising extracting the fraction in the counter-current manner with about 200% by weight of liquid sulphur dioxide alone, extracting the raflinate in the countercurrent manner.with about 200% by weight of liquid sulphur dioxide plus about 20% by weight of benzol, then extracting the second raffinate with a like amount of liquid sulphur dioxide plus a like amount of benzol, and removing from the final raflinate any sulphur dioxideand benzol contained therein.

JQHANNES ARNOLDUS BUCHEL. REYERUS NICOLAAS JAN SAAL.

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' Patent N ."1,'94'5,51e. I ,February'6,1934.

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